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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let s1=Symbol();
        let s2=Symbol('jckd');
        let s3=Symbol();
        console.log(s1,s2,s3);
        //检测：
        console.log(typeof s1);

        // symbol的值唯一：
        console.log(s1==s3);//返回false

        //如果命名相同，则会有覆盖操作，用symbol解决：
        let obj={
            name='lili',
            age=18
        }
        obj.age=19 
        console.log(obj);
    </script>
</body>
</html>